Low-warpage composite film and preparation method thereof

The invention provides a low-warpage composite film and a preparation method thereof, the composite film sequentially comprises a support layer, a substrate layer and an active layer from bottom to top, and the support layer is made of a metal material; the preparation method comprises the following steps: preparing a substrate wafer and a donor wafer; bonding the substrate wafer and the donor wafer to obtain a composite film; chemically and mechanically polishing the substrate layer of the composite film to reduce the roughness of the substrate layer so as to obtain a smooth and flat substrate layer; and a supporting layer is plated on the substrate layer. The substrate layer of the composite film is subjected to magnetron sputtering, and a hard metal layer is plated to serve as a support, so that the deformation degree of a wafer in the subsequent process is reduced, and the purpose of reducing warping is achieved. 本申请提供一种低翘曲的复合薄膜及其制备方法，所述复合薄膜从下至上依次包括支撑层、衬底层和有源层，所述支撑层的材质为金属材料；所述制备方法包括：准备衬底晶圆和供体晶圆；将衬底晶圆与供体晶圆